Process for the production of artificial silk by the copper oxide ammonia stretch spinning process



AUGUST I-IABTMANN, OFXBARMENQ *GERMAnY, 'f'assrenon T Am an BEMeEB No Drawing. Application fileii November 1 3, 1928,5eria1 No. 319;18 9; and iii GermanyllNovember i, 1927.

Patented July 18, 19 33 CORPORATION," on NEW .gonx, N. ,Y,

' It isv kno'wn to produce copper oxideamj nionia silli'hy circulating a portion of the;

- precipitating liquid and replacing the other quantity ofprecipitating liquid' vyas always.

4 supplied freehand the fused precipitating liquid allowed finally to run away to waste; after the copper and ammonia hadlbeen re-. covered. The Whole quantityflotliquidto eniployed has thento b'e continuallyQre-, newed, Which-entailsconsiderableexpense. T r

) Withdrawn is Worked-up until it can be used *again, then thefqufantity of the liquid ithg drawn itself depends on howfar the workportion by freshprecipitatingliqud, coin-d pare Ainercan Letters Patent 957,460. In-

this case, howevcr, the precipitating Was divided up into two partsfin such a,

Fthe ammonia, the copper then precipitating out in the forinof copper hydratc; toY-re-V nianuer that firstol all, the fresh precipitat ing liquid alonewas effective in theiupper part immediately un'der 'the spinning noz ale, and the fresh portion and the portion which had alreadybeen used, andijvhi ch was to be used again, then [arrived vmixed together at the lower portionand 'onlythere were effective; The spinning apparatusitor carryingoutthisprocess required two conductors for theprecipitatingliquids. H i Recently only one precipitatlng hquid and one spinning app aratus have, been used with,

only one conductor; In this: cases the Whole I have 110W discovered that it ishotheCessary to Work alwaysgwith fresh precip tating.

again, if the content of the copper and ammonia are maintained below a certain lll'Illt;

This discovery enables a considerablejsav-k ing in the precipitating liquid-to be effected in 'the process accordinggto the 'present -in-L Vention,

whole precipitating liquid by theprecipitat ing process. Whetherjthe amountcf prei cipitating liquid Withdrawn can be intro-- duced again, after being worked-up, into the circulating liquid,;or' whether it mustbe replaced byvl fresh' precipitating liquid, f

depends upon the kind of'spinning solution and the methodot working-up ernployedl If a cellulose solution produced with the aid PROCESS FOR T E PRonnoTI'o or ARTIFIC AL, s ink BY corrnnoxinn' iui'mtoNIAv Y a STRETCHSPINNING PROCESS a of copper hydrate as one of the starting ma 7 terialsflis 'employed, the portion of precipi tatingfliquidWorked-upmay again be inaf 'troduced into the circulating liquid, since it is possible in thisicase, by distilling Off cover again the ammonia and thecopper v wlthout further const1tnents;remaining be hind in the Worked-up liquid. If; on the other hand, the spinning solution is. pr.0-'-

d-ucea the use of basic cOPPBr sulphate, i

that noconstituents remain behindpand'for 1 this reason, the portion Withdrawn cannot again 'be "conducted into circulating l quid.- In this case it s necessary to 'rey mi placei-thejportion withdrawnfby fresh pree V cipitating liquid. A considerahlesavin-g of precipitating liquid is stilleffected however;

since hithertothe hole-of the precipitating" j,

itJWaswyorked-up. 1

liquid was allowed itofrun to vvWaste evenn if: If-the portion of the precipitating liquid i ns- P re t e h d proceed. This; is

illustrated in r the following; example, "in Which of the precipitating liquid isgei ployed again ithout further. treatment,

While of the liquid is orkedi-up. y the commencement of-the precipitating r a r 7' A. process; 1 cubic-metre. of; precipitating According to my invention, in which only;

liquid ,cbl tains 1.05 kilograms of-ammonia and !O.12'kilograI'nsofcopper injthe form 1 5601 922 y ra etf eie f the p ce-1- p tl n P CQ Sr e/ m n a c te a. V ainountsjtol ikilograinsiand the'icopper f V content tQ 0,1 6'kilogramsq Accordingly Oi fi kilogramsof ammonia must be re1noved,,for

B5? precipitatingjliquidin circulation."The cor; J responding quantity of copper thereupon precipitates outby itself. The portion of 1 precipitating liquid withdrawn, of a? cubic-metre, now contains 0.47 kilograms of example by boiling, from 1 'cubi c inetre of ammonia, While 0.35 kilograms are to be re moved. Thus, 0.12 kilograms of ammonia may remain in thatportionot the precipitating liquid Which is Withdrawn. If it so happens that all the ammonia is to be driven off from the portion withdrawn from circulation, the quantity to be Withdrawn is then reduced accordingly.

What/I claim is I q 1. In the production of artificial silkby the copper oxide ammonia process, the steps cipitating liquid containing copperoxide ammonia, Withdrawing a portion of said stream, removing ammonia from said portion byheatingand separating the copper" precipitated thereby, and returning said treated portionto the recirculated stream.

7 3. In the production ofartificial silkby the copper'oxide ammonia process, the steps "comprising recirculating a'stream of precipitating liquid containing copper oxide ammonia, maintaining the concentrationof the recirculated stream constant by ithdrawing a portion of it and removing sulficient animoiiia'and copper from said portion by heating and separating the copper precipitatedto dilute the recirculated stream to the desired. concentration and returning liquid.

such treated portion to the recirculated stream.

4. A process for the production 'of arti ficial thread by the copper oxide ammonia process, comprising recirculating a precipitating liquidcontaining copper oxide amq q s equivalent to one-third of the total quan- Q monia, Withdraivinga'portion of said liquid,

heating said portion to liberate substantiah ly all of the ammon a and separating'the' copper precipitated thereby, and reintroduci ig said portion into the recirculated 5. A process' for the production of artificial thread by. the" c opper oxide ammonia process, comprising recirculating a prec'ipitating liquid containingcopperuoxide a n'- monia, removing about a third of" said 'pre- P cipitating liquid, treating said removed third to remove ammonia, substantially equivalent to "the amount dissolved by a" single circulation ofthe precipitating liquid,

separating the bomber precipitatedfduri'ng j" ficial thread by the copper oxide ammonia process, comprising recirculating a precipitating liquid containing copper oxide ammonia, Withdrawing a portion of said liquid containing more copper oxide and ammoniathan is dissolved in said liquid during a single circulation of the same, heating said portion to remove sufiicient; ammonia to reduce the remainder of said portion to a concentration such that Whenit is'returned tothe're circulating liquid the mixture Will have the desired concentration separatingthe copper precipitatedf during the heating, 7 s and re-introducing said treated portion to the re-circulating liquid.

7. 'In ,a process for producing cuprammonium filaments, the steps of extrud ng the filaments into a; bath of precipirating liquid,

and When the ammonia content of the pre cipitating liquid approaches 1.4 kilograms per cubic meter, removing. approximately 0.35 kilograms of the ammonia by with drawing a portion of the precipiating liquid and heating it, the liquid so treated be v ing then returned to the said bath. j J r *8. In a process. for producing cuprammonium filaments, the steps of extrudingthe filaments into-a bath of'precipitating liquid,

and when the ammonia content of the precipitating liquid approaches .lA: kilograms per cubic meter and the'copper content ap;

main body of the preaches 0.1 6 kilogramsper cubic meter, re

moving approximately 0.35 kilograms of the ammonia, and the copper, by Withdrawing a portion of the. precipiating liquid and heating it, the liquid so treated being then returned to the main body of the said bath. 9. The process as set forth in claim 'Z,

wherein the portion of the bath Withdrawn tity of the bath."

10.- Ina process ammonia is removed therefrom, and thenre for maintaining the 7 precipitating value of a cuprammonium 'coag-T- ulatingjbath, the steps of using a bath until the. ammonia content approaches 1.4 kilo 1 turning this portion of the bath to'the main ortion, the-portion of the bath being so selected that approximately 0.35 kilograms ofammonia per cubic meter are removed in this Way. v r

' AUGUST HARTMANN. 

